Traffic signal light shroud



April 5, 1966 H. N. sTAA-rs 3,245,075

TRAFFIC SIGNAL LIGHT SHROUD Filed Feb. 24, 1964 FIEE United StatesPatent O 3,245,075 TRAFFIC SIGNAL LIGHT SHRGUD Henry N. Staats, 1344Avenue, Deerfield, lil. Filed Feb. 24, 1%4, Ser. No. 346,866 1 Claim.(Cl. 340-382) This invention relates to a traffic signal light shroudand more particularly to a new means for confining a traic signal lightto viewing :by only the drivers of vehicles moving in the direction forwhich the signal light is placed for control.

Traffic si-gnal lights at road intersections are generally aimed to thetrailic they are to control. In some instances the complication of theterrain, the direction o-f the streets or roads or the number of streetsor roads complicates the problem of so placing the lights that they maybe viewed by the traflic that is intended to respond to the light andnot viewed by the other traiiic. In the past various hoods, split tubes,and short and long tubular members have been placed in front of thelense of the traic light aimed at the traffic intended to view thatlight. These means have been sometimes quite long in an attempt todirect the light only to particular traiiic. Means utilized have beenonly partially successful due to the yfact that reflections ot of theinterior of the tubes have been suiiiciently bright to permit the lightto be viewed by cross traiiic and thus create a confusing and unsafecondition. The dull black paint of prior shrouds has served only todiminish the amount of the reflection that would be obtained over aglossy surface but has not been able to eliminate the reections causingthe diiiiculties. Many bad accidents have occurred as a result of theconfusion caused by a driver being able to see more than his ownparticular set of traflic lights which he should obey and by thosedrivers whose driving habits are such as to make them want to jump alight ahead of receiving the green signal, the starting time beingdetermined by an observation of the cross traics caution signal.

The principal object of this invention is to provide a new and improvedshroud for traic lights which effectively and thoroughly prevents crosstraiiic from viewing a light which it is not intended to see.

Another object is to provide a new shroud which prevents light from atraffic signal to be reflected olf of surfaces of the shroud to theoutside.

Another object is to provide a light shroud for a trafiic signalequipped with means for trapping all lig-ht from the signal impingingupon surfaces of the shroud so that none of the reiiecting light isvisible from outside the shroud.

A further object is to provide new and improved baffles of unique formwhich are capable of trapping all signal light impinging upon the wallof a tubular member extending outwardly in front of the signal light.

Other objects, features .and advantages of the prevent invention will beapparent from the following description of the preferred embodimentsthereof illustrated in the accompanying drawings, in which:

FIGUR-E 1 is a side elevational view of a typical threelight trahiesignal with tubular shrouds thereon;

FIGURE 2f is a fragmentary View of one of the trahie signal lights ofFIGURE l as it appears generally to a driver in a vehicle in crosstraffic;

FIGURE 3 is a front elevational view partially in section takensubstantially along line 2-2 in FIGURE 1 showing the balance of thetraffic light in phantom;

FIGURE 4 is a top plan view of the tratlic light shown in FIGURE 1;

FIGURE 5 is a fragmentary horizontal sectional View through the tubularmember of the light shroud taken 3,245,075 Patented Apr. 5, 1966 ICCsubstantially along line 5-5 in FIGUREI 1 but enlarged thereover yetsmaller than actual size;

FIGURE 6 is an end section looking into the righthand end of the tubeshown in FIGURE v5;

FIGURE 7 is a fragmentary view like FIGURFI 5 showing an alternateconstruction; and

FIGURE 8 is a cross sectional View through the bafiie means illustratedin FIGURE 7.

Trafc lights vary considerably in the number of lights and theirplacement upon supporting framework, posts, arms, cables and the like.It is not intended herein to disclose the various mounting of tratliclights either in number or kind as it forms no part of the presentinvention. In FIGURE 1 a somewhat typical installation of a three-lightsystem mounted upon a pipe standard 10 comprises three boxes 11, 12 and13 stacked in the order speciiied. Within the boxes there is located alamp behind an opening closed by a colored glass lense lending the usualgreen, amber or red color to the traffic signal. At the front of the boxthere is usually a door 14 mounted upon hinges 15 and secured in placeby a thumb screw type of latch 16, whereby the door may be opened togain ,access to the lamp within the box. A tubular shroud 17 may extendforwardly Ifrom a mounting ring 1S secured as by four mounting screws 19to the front of the door. Some manufacturers mount a hood or shroud tothe door in other fashions and by other means. A similar tubular shroud20 may extend 'forwardly from the light housing 12 and a similar shroud21 may extend forwardly from the light housing 11. It maybe noted inFIGURE 1 that the tubular shrouds are directed downwardly fro-m thehorizontal, this being a typical installation Where the light is mountedin an elevated position above the roadway and the shrouds are aimed atthe oncoming traic.

The tubular shrouds are intended to keep cross traic from viewing alight intended to control traiiic on the other streets at anintersection. Many trac light installations are made on the corners ofthe intersection, off but near the roadway. In such instances theappearance of a shroud such as 17 by the cross traic would besubstantially that illustrated in FIGURE 2. It may be noted that theside wall 22 of the shroud 17 is visible in part adjacent the outerextremity Z3 of the tube to the driver of a car stopped at theintersection but in cross trafic so out of posit-ion to look down thelength of the tube to the lense of the traiiic light. The problem,confusion and accidents have occurred because the side wall 22 of thetubular member has been lighted by the traffic signal light suiiicientlyto be viewed 'by the cross traiiic driver.

yThe present invention effectively and absolutely prevents any lightfrom the traiiic signal from impinging upon surfaces of the tubularmember in a fashion that permits such reected light to be viewed fromoutside the tubular member. The basic means -by which such reflectedlight is prevented from being viewed is illustrated in FIGURES 5 and 6.

In the horizontal sectional view of FIGURE S a typical metal tubularmember 17 is shown as extended outwardly from the lense 25 so as to bedirected toward the oncoming traffic which the light is intended tocontrol. A number of baffles is mounted on the interior of the tubularmember adjacent its outer extremity 23. The operational characteristicsof the baffles are such that light 'from the traffic signals mayirnpinge upon one side of the baiiie facing the lense, but the oppositeside of the ibaie facing the outside will remain always in shadow. Whenpainted a dull black, the baie fades into the dull black appearance ofthe shroud itself and is not at all visibly present to the cross traic.

The baiiies may be the smallest in number if each is a part of a rightcircular cone, assuming the tubular member 17 to be a circularcylindrical member, the baille being a surface generated in a particularmanner. Beginning with the baille 26 at the outer extremity of the tube,its generatrix Z7 should extend from the extremity 23 of the tube towarda point 28 in the plane of the lense but radially outside of the tube.The point 28a on the diametrically opposite side also lies on a circleabout the lense and in the plane of the lense which the generatrix 27shown in two positions on FIGURE 5 would move in from the cone of whichthe baille 26 is a part. The apex of .the cone would be at the point 29between the lense and the outer extremity 23 of the tube and on thecenter line of the tube.

It may be observed that a light ray 30 from the outer extremity of thelense directed toward the baille 26 may light the inside surfacewhereupon such light would be reflected to the wall of the tubularmember 17 and trapped. The outer surface of the baille 26 would remainin shadow.

Each of the succeeding baflles 31, 32, 33, 34 and 35 is a part of a conein which the generatrix extends from the base of the baille against theinside wall of the tubular member t the locus of points in the plane ofthe lense illustrated by the points 28 and 28a. The base of eachsucceeding baille may conveniently be placed substantially radiallyopposite the inner extent of the baille. It has been shown that underthis circumstance generally la fair number of bailles may be used sothat only the side facing the lense will be lighted and the oppositeside shall remain in shadow under all circumstances.

A number of baffles is used to line the wall of the shroud sufficientlyfrom the extremity Z3 toward the lense as found necessary in theparticular installation to maintain the outer facing surface on thebailles in shadow. In some installations a tube as long as three feethas been used in front of a traillc light. With the present inventionsuch tubes should be made much shorter and the reilections will becompletely eliminated, thus eliminating the need for the long tube.

While the installation of FIGURES and 6 basically illustrates the modeof operation of the present bailles, manufacturing expediencies permitthe baille structure to be made in convenient forms. In FIGURE 7 atypical tubular member 37 is shown with a baille section 38 of a vinylmaterial formed with ilve individual baille ns or fnlike membersextending inwardly from an integral or a common base 39. The fins 40should be very thin and if sufficiently close together, may be extendinginwardly from the wall of the tubular member but a short distance. Theangle a between the fins and the wall should 4be the same and no smallerthan the angle b between the baille 35 and the wall of the tube 17 shownin FIGURE 5. Preferably, the angle of all the fins will be made the samefor convenience in manufacture. A typical structure is illustrated inthe cross section of FIGURE 8 where the entire member is extruded in avinyl material of dull black color, the ilns being integral with thebase 39. A suitable length of the extrusion is cut on a bias and thenplaced inside the tubular member 37. When the joint in the baillesection is placed at the top of the tube or at the bottom of the tube,it is generally in a location where it can not be viewed by traillc andthus is inconsequential.

A typical iln such as the fin 40 may be individually made or made in agang of fins as illustrated in FIG- URES 7 and 8. Many tubular likesections are about eight inches in diameter and it has been found that aiin about one-fourth inch in length with about one-fourth inch distancebetween the iins or bafiles will sufficiently trap light on the interiorof the tube while not diminishing materially the size of the traillcsignal to be viewed. In certain instances a single fin and base may bespirally placed in the tube if desired with the lap in the spiral beingat the top or bottom of the tube.

The foregoing detailed description has been given for clearness ofunderstanding only and no unnecessary limitations should be understoodtherefrom as some modifications will be obvious to those skilled in theart.

I claim:

A traillc signal 4light shroud for preventing reflection of light tolateral traillc vehicle drivers, comprising: a tubular member extendingoutwardly from the signal light toward oncoming trailic moving towardthe light in the direction of the extent of the tubular member, aplurality of frusto-conical baille members axially spaced in closeproximity of each other within said tubular member and extending inwardfrom substantially the outer end of said tubular member, the axes ofsaid frustoconical members being substantially the axis of said tubularmember, the projected apexes of said frusto-conical members ing inwardtoward the signal light source, each baille having a ilrst surfacedirected toward the light source and an opposite surface facing outwardsaid tubular member being in shadow relative to the light source.

References Cited by the Examiner UNITED STATES PATENTS 1,266,524 5/1918one 24o-46.41 1,864,418 6/1952 Ehlers 240-46.o1 2,190,526 2/1'940 wens340-582 2,540,389 2/1951 Powier 340-84 FOREIGN PATENTS 464,952 9/1928Germany. 62,573 3/1926 sweden.

NEIL C. READ, Primary Examiner.

W. C. GLEICHMAN, I. I. LEVIN, Assistant Examiners.

